ALS is a progressive neurodegenerative disease linked to the progressive death of motor neurons, the nerve cells that control the voluntary muscles. The disease attacks the peripheral motor neurons, in direct relation with the muscles, and the central motor neurons located in the motor cortex, in the brainstem, the medulla oblongata and the spinal cord.
This systematized degeneration of the motor neurons results in numerous motor disorders such as spasms linked to muscle-tone dysregulation, increased deep tendon reflexes, muscle twitching and paralysis associated with muscle atrophy. There are few or no other signs of neurological impairment, including no sensory, oculomotor or mental disorders. Other additional symptoms accompany the motor disorders, namely: constipation, weight loss, pain, edema, vasomotor disorders, sleep and respiratory disorders.
There are three major forms of ALS determined by the site of onset of the attack of the peripheral motor neurons: the bulbar or cervical-brachial form, the upper form (central and motor cortex motor neurons) and the lower or lumbosacral form.
The spinal onset form is linked to the initial attack of the motor neurons of the spinal cord, resulting in movement disorders of the upper and lower limbs.
The bulbar form is linked to the initial attack of motor neurons of the brainstem and causes speech and swallowing disorders.
There is also a form of ALS that begins with an attack of the motor neurons of the motor cortex.
Whatever the initial form, the neurodegeneration advances progressively to a form involving multiple disabilities that influence the prognosis. In the majority of cases, death is due to respiratory failure aggravated by secondary bronchial infections. Median survival is 3-5 years in over 70% of cases.
Whatever the initial form, the neurodegeneration advances progressively to a form involving multiple disabilities that influence the prognosis. In the majority of cases, death is due to respiratory failure aggravated by secondary bronchial infections. Median survival is 3 to 5 years in more than 70% of cases.
Several genes (SOD1, ALS2, SPG20, UBQL2, C90RF72, etc.) have been identified in familial forms of ALS. However, these genetic mutations only account for a small percentage of patients with ALS. In most cases, ALS occurs sporadically. We do not note any distribution gradient around the world as is the case for other neurological diseases like Multiple Sclerosis, however we do note regions (or isolates) with higher prevalence.
There is currently no etiological treatment capable of halting the progression of ALS. The only product, Rilutek or Riluzole, is a glutamate inhibitor. It offers the patient a median survival of three to six more months, which is not very much. Furthermore, this product has numerous side effects (liver toxicity). Patient management is limited to the prevention of movement dysfunctions, help with disabilities and symptomatic treatments of the disease. Furthermore, this management requires the involvement of professionals and necessitates hospitalization and special monitoring, which is onerous for the patients and the community.
The search for effective treatments for ALS capable of controlling the progression of the disease that are easy to administer with few or no side effects is therefore a priority in human health.
For over 20 years, ALS has been the subject of numerous fundamental biomedical research projects that have established, among other things, that:                neurodegeneration is linked to a hyperproduction of free radicals and various reactive oxygen species resulting in endogenous protein modifications, protein aggregation and neuronal death (apoptosis);        external bacterial, viral or toxic stimuli, pollutants, intense muscle exercises and repeated electrical discharges participate in the acceleration of neurodegeneration;        when the pathogenic processes are involved in ALS, no research has been able to identify products with inhibitory or even stabilizing activity.        
Despite numerous clinical trials, conducted over more than twenty years, no effective treatment exists to date.